Title: Managing /etc/hosts on NixOS

	Title: Managing /etc/hosts on NixOS
	Author: Solène
	Date: 14 September 2021
	Tags: nixos
	Description:

	# Introduction

	This is a simple article explaining how to manage entries in /etc/hosts
	in a NixOS system. Modifying this file is quite useful when you need
	to make tests on a remote server while its domain name is still not
	updated so you can force a domain name to be resolved by a given IP
	address, bypassing DNS queries.

	NixOS being what is is, you can't modify the /etc/hosts file directly.

	NixOS stable documentation about the extraHosts variable

	# Configuration

	In your /etc/nixos/configuration.nix file, you have to declare the
	variable networking.extraHosts and use "\n" as separator for entries.

	```NixOS configuration file sample
	networking.extraHosts = "1.2.3.4 foobar.perso.pw\n1.2.3.5 foo.perso.pw";
	```

	or as suggested by @[email protected] on Mastodon, you can use
	multiple lines in the string as follow (using two single quotes
	character):

	```NixOS configuration file sample
	networking.extraHosts = ''
	1.2.3.4 foobar.perso.pw
	1.2.3.5 foo.perso.pw
	'';
	```

	The previous pieces of configuration will associate "foobar.perso.pw"
	to IP 1.2.3.4 and "foo.perso.pw" to IP 1.2.3.5.

	Now, I need to rebuild my system configuration and use it, this can be
	done with the command `nixos-rebuild switch` as root.